This FAQ is designed to answer common questions about sending e-mail from MVS.
What are my options for sending e-mail from MVS?
What is SMTP? What is its purpose?
What is RFC822?
What is MIME and why is it important?
What does a SMTP data stream consist of?
How can I send attachments?
How can I prevent users from pretending to be someone else when they send mail?
How does SMTP-Send insulate me from the various Internet Protocols?
Where can I get more information about the IBM SMTP Server?
Do I have to use the IBM SMTP Server?
My SMTP server doesn't recognize the @ character in my e-mail addresses. How can I send mail?
How can I get my SMTP Server to relay all mail to another SMTP mail server?
How do I prevent spammers from hijacking my IBM SMTP Server?
How do I prevent spammers from hijacking my IBM SMTP Server?

• Don't connect directly to the Internet. A firewall can be used to block any unwanted traffic. If you don't use your SMTP server to receive external e-mail, ask your firewall people to disable port 25 to inbound traffic. That way spammers can't send any inbound relay traffic.
• Relay all of your e-mail to another non-MVS SMTP server that can detect the unwanted relay traffic.
• If you send all of your e-mail throught the Spool/NJE interface you can set MAXMAILBYTES 1 which means you only accept 1 byte messages over TCP connections
• You can code the SMTPEXIT to inspect all traffic coming into your SMTP Server via TCP/IP. With the addtion of APAR PQ13476 you can also inspect data entering via the JES Spool. Refer to Communications Server IP Configuration Reference for additional information on SMTP Exits.
• Use SMTP-Send's Spool Server instead of IBM's SMTP Server to only accept SMTP traffic from the spool.